1. Field of the Invention
The present invention relates to a linear sliding guide bearing, and in particular, to an improvement therein.
2. Description of the Related Art
Various prior art linear sliding guide bearings have been known. For example, Japanese Patent Laid-Open Publication No. 47-43838 discloses a linear sliding guide bearing in which a dovetail slot is formed in a metallic guide rail. A sliding member made of an elastic plastic and having a guide face formed in a slightly convex shape is mounted in the dovetail slot. A table (slider) is fixed to the sliding member with a bolt (first prior art example).
Furthermore, Japanese Utility Model Laid-Open Publication No. 59-58215 discloses a sliding unit including a guide rail formed by stamping a plate material and a table (slider) having a flat plate shape and slidably fitted in the guide rail. A base portion secured to a base, side wall portions bent upwardly from both edges of the base portion and opposing to each other sandwiching an axis line of the rail, sliding portions bent outwardly from upper ends of the side wall portions in parallel with the base portions, and holding portions bent downwardly from end portions of the sliding portions towards the base portions are integrally formed. The table is formed of a plate member having a sliding member integrally attached to a lower surface. A gib having a holding piece which is formed by stamping and fitted into a holding portion of the rail is provided integrally on the table. The gib of the table is slidingly in contact with the sliding portion and the holding portion of the rail, and the sliding portion and the holding portion are fitted so that they are held vertically (second prior art example).
Moreover, a catalog 85'-2, No. JC00-100, pages 2-31, of OILESS KOZYO K.K. discloses an oiless slide shifter in which a liner (sliding member) sliding on the upper surface of the guide rail, and a gib (sliding member) sliding on the side surfaces are both formed by an oiless metal (oleo-sintered alloy), and the slider and gib are fixed to the slider by a bolt (third prior art example).
Furthermore, Japanese Utility Model Publication No. 52-12843 discloses a mechanism in which a movable member is freely slidable with respect to a guide bar through a plurality of open type slide ball bearings along an axis line of the guide rail. In this mechanism, an elastic deformation portion formed with a dovetail slot is claimed to the movable member to thereby apply a pre-load to the slide ball bearings.
However, in the first prior art example, a head of a bolt for adjusting gaps between the table and the guide rail, and between the table and the sliding member faces an inner surface of the dovetail slot of the guide rail. As a result, in order to adjust the gaps, the table must be removed from the guide rail each time an adjustment is made. This is not a simple task and is troublesome. Furthermore, since the guide surface of the plastic sliding portion is formed in the convex shape, a problem results in that it is quickly worm which could cause rattling.
Furthermore, in the second prior art example, the guide rail and the flat-plate type table slidably fitted to the guide rail are merely formed by stamping a plate member and assembled each to each other. Accordingly, it is small and light weight. However, no means is provided for adjusting the gaps between the guide rail and the table. Thus, it has been impossible to adjust the gaps.
Moreover, in the third prior art example, the sliding member interposed between the guide rail and the slider is fixed by the bolt. As a result, it is difficult to make it small and thin. The adjustment of the gap between the guide rail and the slider is effected by pressing the sliding member having a weak strength by a bolt, and also by adjusting the degree of clamping of a fixing bolt which is engaged with a screw hole provided in the sliding member. For this reason, it is difficult to perform a fine adjustment of the gap. Further, there are holes for fixing bolts and recesses on the upper surface of the guide rail. Consequently, dust is apt to be deposited on the upper surface of the guide rail, and this poses a problem in that the lip portion of the wiper seal is held by the edge of the recesses so as to disturb the smooth operation of the slider.